Manufacturing method for laminated iron core

ABSTRACT

A manufacturing method for a laminated iron core includes conveying a sheet steel strip in an intermittent manner in a lift up state, with upward movement of the strip being limited by a guiding member provided on a lower holder; punching an outer shape of each iron core laminae; and applying adhesive agent to a surface of the strip before the punching. The adhesive agent is applied in a state in which a pilot pin is inserted in a pilot hole of the strip and when the strip is about to be pressed against or is being pressed against the die plate by a stripper provided on an upper holder. After application of the adhesive agent, the strip is returned to the lift up state by raising the upper holder, with a lifter and the stripper plate being in abutment with the lower and upper surfaces of the strip, respectively.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Stage entry of InternationalApplication Number PCT/JP2017/000359 filed under the Patent CooperationTreaty having a filing date of Jan. 9, 2017, which is incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates to a manufacturing apparatus and amanufacturing method for a laminated iron core, and particularly to amanufacturing apparatus and a manufacturing method for a bonded-typelaminated iron core formed by bonding a plurality of stacked iron corelaminae to each other by an adhesive agent.

BACKGROUND ART

As a laminated iron core used in a stator and a rotor of a rotaryelectric machine, a bonded-type laminated iron core is known. Thebonded-type laminated iron core is formed as follows. That is, iron corelaminae are punched from a sheet steel strip conveyed in an intermittentmanner by a progressive die including a plurality of punching dies (diesets) each formed by a punch and a die, and the iron core laminae aresequentially stacked in a die, and are bonded to each other by anadhesive agent such as an epoxy resin adhesive agent (Patent Literatures1 and 2).

PRIOR ART DOCUMENTS Patent Literature

Patent literature 1: Japanese Patent Laid-Open No. 2001-321850

Patent literature 2: Japanese Patent Laid-Open No. 2009-124828

SUMMARY OF INVENTION Technical Problem

The application of the adhesive agent to an adhesive agent applyingsurface of each iron core lamina (sheet steel strip) needs to beaccurately performed on predetermined positions on the adhesive agentapplying surface so that a bond strength is obtained as designed anddripping and the like of the adhesive agent to the outside is prevented.In addition, it is required that the adhesive agent on the adhesiveagent applying surface is not spread or scattered to the surroundingsdue to the vibration and the like of the iron core lamina (sheet steelstrip) caused when the iron core lamina is moved.

The problem to be solved by the present invention is to accurately applyan adhesive agent on an adhesive agent applying surface.

Solution to Problem

A manufacturing apparatus for a laminated iron core according to thepresent invention is a manufacturing apparatus for a laminated iron coreformed by stacking and bonding iron core laminae each formed by punchinga sheet steel strip into a predetermined shape, the manufacturingapparatus including: an upper holder and a lower holder; a plurality ofpunches and dies provided on the upper holder and the lower holder,respectively, the plurality of punches and dies sequentially punchingthe iron core laminae from the sheet steel strip conveyed in anintermittent manner; a guiding member provided on the lower holder, theguiding member guiding conveyance of the sheet steel strip along anintermittent conveyance direction of the sheet steel strip and limitingupward movement of the sheet steel strip; and an adhesive agent applyingapparatus provided on at least one of the upper holder and the lowerholder, the adhesive agent applying apparatus applying an adhesive agentto an adhesive agent applying surface at a section of the sheet steelstrip corresponding to each iron core lamina.

According to this configuration, the adhesive agent is applied to theadhesive agent applying surface in a state in which the upward movementof the sheet steel strip is limited by the guiding member, and hence theadhesive agent is accurately applied on the adhesive agent applyingsurface.

The guiding member has a structure for limiting the movement of thesheet steel strip in the right and left directions by coming intoabutment with the sheet steel strip in addition to a structure forlimiting the upward movement of the sheet steel strip by coming intoabutment with the sheet steel strip, and guides the intermittentconveyance of the sheet steel strip.

In that case, the adhesive agent is applied to the adhesive agentapplying surface in a state in which the movement of the sheet steelstrip is limited in the right and left directions in addition to theupward direction, and hence the adhesive agent is applied to theadhesive agent applying surface in an even more accurate manner.

The manufacturing apparatus for a laminated iron core according to thepresent invention preferably further includes a pilot pin provided onthe upper holder, the pilot pin being configured to be inserted througha pilot hole formed in the sheet steel strip so as to performpositioning of the sheet steel strip in each conveyance position.

According to this configuration, the adhesive agent is applied to theadhesive agent applying surface in a state in which the pilot pin isinserted through the pilot hole formed in the sheet steel strip, andhence the adhesive agent is accurately applied on the adhesive agentapplying surface.

The manufacturing apparatus for a laminated iron core according to thepresent invention preferably further includes a stripper plate providedon the upper holder so as to be displaceable in a vertical direction,the stripper plate having a lower surface opposed to upper surfaces ofthe dies.

According to this configuration, the vertical movement of the sheetsteel strip can be limited by the stripper plate, and hence the adhesiveagent is accurately applied on the adhesive agent applying surface.

The manufacturing apparatus for a laminated iron core according to thepresent invention preferably further includes a stripper spring thatbiases the stripper plate toward the lower holder, and the stripperplate is configured to press the sheet steel strip against the uppersurfaces of the dies by a spring force of the stripper spring.

According to this configuration, the adhesive agent may be applied tothe adhesive agent applying surface when the sheet steel strip is aboutto be pressed against or is being pressed against the dies by thestripper plate, and the adhesive agent is accurately applied on theadhesive agent applying surface.

In the manufacturing apparatus for a laminated iron core according tothe present invention, the stripper plate is preferably configured topress the sheet steel strip against the upper surfaces of the dies untilthe punches come out of the dies, and more preferably until the punchescome out of the sheet steel strip.

According to this configuration, in the ascending process of the upperholder after the punching, a state in which the sheet steel strip ispressed against the upper surface of the die by the stripper plate ismaintained until the punches come out of the die or until the punchescome out of the sheet steel strip, and hence the swinging of the sheetsteel strip in the ascending process of the upper holder is suppressed,and the scattering of the adhesive agent applied on the sheet steelstrip is suppressed.

In the manufacturing apparatus for a laminated iron core according tothe present invention, the pilot pin preferably includes a straightshaft portion, and the straight shaft portion is preferably positionedto protrude downward from the lower surface of the stripper plate in astate in which the stripper plate is in a most lowered position withrespect to the upper holder by being biased by the stripper spring.

According to this configuration, in the descending process of the upperholder, the straight shaft portion of the pilot pin enters the pilothole before the lower surface of the stripper plate comes into abutmentwith the sheet steel strip, and hence the positioning of the sheet steelstrip is smoothly performed without being obstructed by the restrictionof the sheet steel strip by the stripper plate.

The manufacturing apparatus for a laminated iron core according to thepresent invention preferably further includes a plurality of liftersprovided on the lower holder so as to be displaceable in a verticaldirection, the plurality of lifters separating the sheet steel stripfrom upper surfaces of the dies by coming into abutment with a lowersurface of the sheet steel strip.

According to this configuration, the sheet steel strip can be lifted upfrom the upper surfaces of the dies when the sheet steel strip isconveyed in an intermittent manner, and thus, even when the adhesiveagent applying surface is the lower surface of the sheet steel strip,the adhesive agent applied on the adhesive agent applying surface is notrubbed by the upper surfaces of the dies.

The manufacturing apparatus for a laminated iron core according to thepresent invention preferably further includes: a plurality of liftersprovided on the lower holder so as to be displaceable in a verticaldirection, the plurality of lifters separating the sheet steel stripfrom upper surfaces of the dies by coming into abutment with a lowersurface of the sheet steel strip; and a plurality of lifter springs thatbias the lifters upward so as to separate the sheet steel strip from theupper surfaces of the dies, with the stripper plate being in abutmentwith an upper surface of the sheet steel strip and the lifters being inabutment with the lower surface of the sheet steel strip, when thestripper plate ascends.

According to this configuration, the iron core lamina is returned to thelift up state (separated state), with the iron core lamina beingvertically supported by the lifter and the stripper plate, after theapplication of the adhesive agent, and hence the swinging of the sheetsteel strip in the lift up process of the sheet steel strip issuppressed, and the scattering of the adhesive agent applied on thesheet steel strip is suppressed.

In the manufacturing apparatus for a laminated iron core according tothe present invention, each of the lifters preferably serves as theguiding member.

According to this configuration, the number of parts is reduced.

When the lifters also serve as the guiding members, the lifters onlyneed to be formed by lifter pins each having a circumferential grooveformed in the outer circumference of an upper part thereof and have astructure such that the right and left side edge portions of the sheetsteel strip enter the circumferential grooves. In that case, in a statein which the sheet steel strip is lifted up by the lifters, the upwardmovement and the downward movement of the sheet steel strip are limitedin accordance with the vertical widths of the circumferential grooves,and the flapping of the sheet steel strip in the intermittent conveyanceis suppressed.

In the manufacturing apparatus for a laminated iron core according tothe present invention, the adhesive agent applying apparatus ispreferably a transfer type including a plurality of discharge holes thatdischarge the adhesive agent toward the adhesive agent applying surfaceso as to transfer the adhesive agent to each of a plurality ofpredetermined positions on the adhesive agent applying surface.

According to this configuration, the adhesive agent is accuratelyapplied on the adhesive agent applying surface by transferring.

In the manufacturing apparatus for a laminated iron core according tothe present invention, the adhesive agent applying apparatus preferablyincludes: an adhesive agent supplying apparatus that supplies theadhesive agent to each of the discharge holes with a predeterminedpressure; and an advance-retreat driving apparatus that moves thedischarge holes between a transfer position in which transferring of theadhesive agent to the adhesive agent applying surface is possible and anon-transfer position in which the discharge holes are retreated fromthe transfer position and transferring of the adhesive agent is notpossible.

According to this configuration, the transfer and the non-transfer ofthe adhesive agent on the adhesive agent applying surface areselectively set only by selectively setting the position of thedischarge holes to either one of the transfer position and thenon-transfer position.

The manufacturing apparatus for a laminated iron core according to thepresent invention is a manufacturing apparatus for a laminated iron coreformed by stacking and bonding iron core laminae each formed by punchinga sheet steel strip into a predetermined shape, the manufacturingapparatus including: an upper holder and a lower holder; a plurality ofpunches and dies provided on the upper holder and the lower holder, theplurality of punches and dies sequentially punching the iron corelaminae from the sheet steel strip conveyed in an intermittent manner; apilot pin provided on the upper holder, the pilot pin being configuredto be inserted through a pilot hole formed in the sheet steel strip soas to perform positioning of the sheet steel strip in each conveyanceposition; a stripper plate provided on the upper holder so as to bedisplaceable in a vertical direction, the stripper plate having a lowersurface opposed to upper surfaces of the dies; a stripper spring thatbiases the stripper plate toward the lower holder; a plurality oflifters provided on the lower holder so as to be displaceable in avertical direction, the plurality of lifters coming into abutment with alower surface of the sheet steel strip; a plurality of lifter springsthat bias the lifters upward so as to lift the sheet steel strip fromthe upper surfaces of the dies, with the stripper plate being inabutment with an upper surface of the sheet steel strip and the liftersbeing in abutment with the lower surface of the sheet steel strip, whenthe stripper plate ascends; and an adhesive agent applying apparatusprovided on at least one of the upper holder and the lower holder, theadhesive agent applying apparatus applying an adhesive agent to anadhesive agent applying surface at a section of the sheet steel stripcorresponding to each iron core lamina.

According to this configuration, the adhesive agent may be applied tothe adhesive agent applying surface in a state in which the pilot pin isinserted through the pilot hole in the sheet steel strip and when thesheet steel strip is about to be pressed against or is being pressedagainst the upper surfaces of the dies by the stripper plate, and thus,the adhesive agent is accurately applied on the adhesive agent applyingsurface. In addition, the sheet steel strip is returned to the lift upstate with the sheet steel strip being vertically supported by thelifters and the stripper plate after the application of the adhesiveagent, and hence the swinging of the sheet steel strip in the raisingprocess of the sheet steel strip is suppressed, and the scattering ofthe adhesive agent applied on the sheet steel strip is suppressed.

A manufacturing method for a laminated iron core according to thepresent invention is a manufacturing method for a laminated iron coreformed by stacking and bonding iron core laminae each formed by punchinga sheet steel strip into a predetermined shape with use of a pressapparatus including an upper holder and a lower holder, themanufacturing method including: a conveyance step of conveying the sheetsteel strip in an intermittent manner, with an upward movement of thesheet steel strip being limited and conveyance of the sheet steel stripalong an intermittent conveyance direction being guided by a guidingmember provided on the lower holder; a punching step of punching anouter shape of each of the iron core laminae with a punch and a dieprovided on the upper holder and the lower holder by lowering the upperholder; and an applying step of applying an adhesive agent to anadhesive agent applying surface of the sheet steel strip with anadhesive agent applying apparatus provided on at least one of the upperholder and the lower holder before the punching step.

According to this manufacturing method, the adhesive agent is applied tothe adhesive agent applying surface in a state in which the intermittentconveyance of the sheet steel strip is guided by the guiding member andthe upward movement of the sheet steel strip is limited by the guidingmember, and hence the adhesive agent is accurately applied on theadhesive agent applying surface.

In the manufacturing method for a laminated iron core according to thepresent invention, the conveyance step preferably includes conveying thesheet steel strip in an intermittent manner in a lift up state in whichthe sheet steel strip is separated from an upper surface of the dieprovided on the lower holder by a lifter provided on the lower holder soas to be vertically movable and biased upward by a lifter spring in araised state of the upper holder.

According to this manufacturing method, even when the adhesive agentapplying surface is the lower surface of the sheet steel strip, theadhesive agent applied on the adhesive agent applying surface is notrubbed by the upper surface of the die.

The manufacturing method for a laminated iron core according to thepresent invention preferably further includes a pilot insertion step ofinserting a pilot pin provided on the upper holder into a pilot holeformed in the sheet steel strip in middle of descent of the upper holderafter the conveyance step finishes.

According to this manufacturing method, the positioning of the sheetsteel strip is accurately performed, and hence the adhesive agent isaccurately applied on the adhesive agent applying surface.

The manufacturing method for a laminated iron core according to thepresent invention preferably further includes a pressing step ofpressing, in middle of descent of the upper holder after the pilotinsertion step finishes, the sheet steel strip against the upper surfaceof the die provided on the lower holder with a stripper plate hung fromthe upper holder by a stripper spring, along with a descending movementof the lifter.

According to this manufacturing method, the sheet steel strip is pressedagainst the upper surface of the die after the pilot insertion stepfinishes, in other words, the pilot pin is inserted into the pilot holein the sheet steel strip before the sheet steel strip is pressed againstthe upper surface of the die and is restricted, and hence the pilot pinis smoothly inserted into the pilot hole.

In the manufacturing method for a laminated iron core according to thepresent invention, the applying step preferably includes applying theadhesive agent in a state in which the pilot pin is inserted in thepilot hole and when the sheet steel strip is about to be pressed againstor is being pressed against the upper surface of the die by the stripperplate along with the descending movement of the lifter, and returningthe sheet steel strip to the lift up state by raising the upper holderafter application of the adhesive agent finishes, with the lifter beingin abutment with a lower surface of the sheet steel strip along with anascending movement of the lifter and with the stripper plate being inabutment with the upper surface of the sheet steel strip.

According to this manufacturing method, the adhesive agent is applied tothe adhesive agent applying surface when the sheet steel strip is aboutto be pressed against or is being pressed against the die by thestripper plate, and hence the adhesive agent is accurately applied onthe adhesive agent applying surface. In addition, the swinging of thesheet steel strip in the ascending process of the upper holder issuppressed, and the scattering of the adhesive agent applied on thesheet steel strip is suppressed.

The manufacturing method for a laminated iron core according to thepresent invention is a manufacturing method for a laminated iron coreformed by stacking and bonding iron core laminae each formed by punchinga sheet steel strip into a predetermined shape with use of a pressapparatus including an upper holder and a lower holder, themanufacturing method including: a conveyance step of conveying the sheetsteel strip in an intermittent manner in a lift up state in which thesheet steel strip is separated from upper surfaces of dies provided onthe lower holder by a lifter provided on the lower holder so as to bevertically movable and biased upward by a lifter spring in a raisedstate of the upper holder; a pilot insertion step of inserting a pilotpin provided on the upper holder into a pilot hole formed in the sheetsteel strip in middle of descent of the upper holder after theconveyance step finishes; a pressing step of pressing, in middle ofdescent of the upper holder after the pilot insertion step finishes, thesheet steel strip against the upper surfaces of the dies provided on thelower holder with a stripper plate hung from the upper holder by astripper spring, along with a descending movement of the lifter; apunching step of sequentially punching an inner shape and an outer shapeof each iron core lamina with a plurality of die sets each formed by apunch and a die provided on the upper holder and the lower holder at aplurality of press positions set in a row in an intermittent conveyancedirection at intervals, by further lowering the upper holder after thepressing step finishes; and an applying step of applying an adhesiveagent to the adhesive agent applying surface of the sheet steel stripwith an adhesive agent applying apparatus set between the press positionfor punching the inner shape and the press position for punching theouter shape so as to be in a row with the press positions and providedon at least one of the upper holder and the lower holder, in which theapplying step includes applying the adhesive agent in a state in whichthe pilot pin is inserted in the pilot hole and when the sheet steelstrip is about to be pressed against or is being pressed against theupper surfaces of the dies by the stripper plate along with thedescending movement of the lifter, and returning the sheet steel stripto the lift up state by raising the upper holder after application ofthe adhesive agent finishes, with the lifter being in abutment with alower surface of the sheet steel strip along with an ascending movementof the lifter and with the stripper plate being in abutment with theupper surface of the sheet steel strip.

According to this manufacturing method, the adhesive agent is applied tothe adhesive agent applying surface in the state in which the pilot pinis inserted through the pilot hole in the sheet steel strip and when thesheet steel strip is about to be pressed against or is being pressedagainst the upper surface of the die by the stripper plate, and hencethe adhesive agent is accurately applied on the adhesive agent applyingsurface. In addition, after the application of the adhesive agent, thesheet steel strip is returned to the lift up state with the sheet steelstrip being vertically supported by the lifter and the stripper plate,and hence the swinging of the sheet steel strip in the lift up processof the sheet steel strip is suppressed and the scattering of theadhesive agent applied on the sheet steel strip is suppressed.

In the manufacturing method for a laminated iron core according to thepresent invention, the applying step preferably includes a step oftransferring the adhesive agent to each of a plurality of predeterminedpositions on the adhesive agent applying surface by discharging theadhesive agent toward the adhesive agent applying surface from each of aplurality of discharge holes.

According to this manufacturing method, the adhesive agent is applied tothe adhesive agent applying surface finely and accurately bytransferring.

In the manufacturing method for a laminated iron core according to thepresent invention, each iron core lamina includes a plurality of teethportions, and has at least one of the application points placed on theteeth portion.

According to this manufacturing method, the bonding between adjacentiron core laminae is performed also in the teeth portions, and thelaminated iron core having a high bond strength is produced.

Advantageous Effect of Invention

According to the manufacturing apparatus and the manufacturing methodfor a laminated iron core of the present invention, the adhesive agentis accurately applied on the adhesive agent applying surface.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plan view illustrating an example of an iron core laminaused in a stator of a stepping motor.

FIG. 2 is an explanatory view illustrating a strip layout in aprogressive die machine used in the manufacture of the iron core laminaillustrated in FIG. 1.

FIG. 3 is a plan view illustrating an iron core lamina schematicallyillustrating the iron core lamina manufactured by a manufacturingapparatus and a manufacturing method for the laminated iron coreaccording to the present invention.

FIG. 4 is an explanatory view illustrating one embodiment of a striplayout in a progressive die machine used in the manufacture of thelaminated iron core illustrated in FIG. 3.

FIG. 5 is a schematic configuration diagram illustrating one embodimentof a manufacturing apparatus for a laminated iron core according to thepresent invention.

FIG. 6 is a cross-sectional view illustrating an adhesive agentapparatus used in the manufacturing apparatus for the laminated ironcore according to this embodiment.

FIG. 7 is an enlarged cross-sectional view of the main section of theadhesive agent apparatus according to this embodiment.

FIG. 8A is a cross-sectional view of an inner shape punching station ofthe manufacturing apparatus according to this embodiment in a top deadcenter state.

FIG. 8B is a cross-sectional view of an adhesive agent applying stationof the manufacturing apparatus according to this embodiment in the topdead center state.

FIG. 9A is a cross-sectional view of the inner shape punching station ofthe manufacturing apparatus according to this embodiment in a descendingprocess 1.

FIG. 9B is a cross-sectional view of the adhesive agent applying stationof the manufacturing apparatus according to this embodiment in thedescending process 1.

FIG. 10A is a cross-sectional view of the inner shape punching stationof the manufacturing apparatus according to this embodiment in adescending process 2.

FIG. 10B is a cross-sectional view of the adhesive agent applyingstation of the manufacturing apparatus according to this embodiment inthe descending process 2.

FIG. 11A is a cross-sectional view of the inner shape punching stationof the manufacturing apparatus according to this embodiment in adescending process 3.

FIG. 11B is a cross-sectional view of the adhesive agent applyingstation of the manufacturing apparatus according to this embodiment inthe descending process 3.

FIG. 12A is a cross-sectional view of the inner shape punching stationof the manufacturing apparatus according to this embodiment in a bottomdead center state.

FIG. 12B is a cross-sectional view of the adhesive agent applyingstation of the manufacturing apparatus according to this embodiment inthe bottom dead center state.

FIG. 13A is a cross-sectional view of the inner shape punching stationof the manufacturing apparatus according to this embodiment in anascending process 1.

FIG. 13B is a cross-sectional view of the adhesive agent applyingstation of the manufacturing apparatus according to this embodiment inthe ascending process 1.

FIG. 14A is a cross-sectional view of the inner shape punching stationof the manufacturing apparatus according to this embodiment in anascending process 2.

FIG. 14B is a cross-sectional view of the adhesive agent applyingstation of the manufacturing apparatus according to this embodiment inthe ascending process 2.

FIG. 15A is a cross-sectional view of the inner shape punching stationof the manufacturing apparatus according to this embodiment in anascending process 3.

FIG. 15B is a cross-sectional view of the adhesive agent applyingstation of the manufacturing apparatus according to this embodiment inthe ascending process 3.

FIG. 16 is an enlarged cross-sectional view of a lift-up portion of themanufacturing apparatus according to this embodiment in the top deadcenter state.

FIG. 17 is an enlarged cross-sectional view of the lift-up portion ofthe manufacturing apparatus according to this embodiment in thedescending process 2.

FIG. 18 is an enlarged cross-sectional view of the lift-up portion ofthe manufacturing apparatus according to this embodiment in the bottomdead center state.

FIG. 19 is an enlarged cross-sectional view of the lift-up portion ofthe manufacturing apparatus according to this embodiment in theascending process 1.

FIG. 20 is an explanatory view illustrating an example of anotherembodiment of a strip layout in a progressive die machine used in themanufacture of the laminated iron core illustrated in FIG. 3.

FIG. 21 is an explanatory view illustrating an example of anotherembodiment of a strip layout in a progressive die machine used in themanufacture of the laminated iron core illustrated in FIG. 3.

FIG. 22A is a cross-sectional view of an inner shape punching station ofa manufacturing apparatus according to another embodiment in a top deadcenter state.

FIG. 22B is a cross-sectional view of an adhesive agent applying stationof a manufacturing apparatus according to another embodiment in a topdead center state.

DESCRIPTION OF EMBODIMENTS

Preferred embodiments according to the present invention are describedwith reference to the accompanying drawings.

First, as a specific example of a laminated iron core, a laminated ironcore used in a stator of a stepping motor is described with reference toFIG. 1.

The laminated iron core is obtained by stacking a plurality of iron corelaminae A having the same shape. Each iron core lamina A is obtained bypunching a sheet steel strip or a strip F into a predetermined shape bypress working using a progressive die, and includes an annular yokesection B obtained by outer shape punching, a plurality of teethportions (magnetic pole portions) C formed by inner shape punching andprotruding radially inward from the yoke section B, and a plurality ofthrough holes D formed in the yoke section B through punching. Adjacentiron core laminae A are bonded to each other by an adhesive agentapplied to a plurality of application points E1 and E2 on one surface(adhesive agent applying surface) of the yoke section B and the teethportions C in a round dot shape.

The adhesive agent used here includes an anaerobic adhesive agent (anadhesive agent+a hardening accelerator), a one-component epoxy resinadhesive agent, a two-component epoxy resin adhesive agent (a firstadhesive agent liquid+a second adhesive agent liquid or a main agent+aninitiator), a thermosetting adhesive agent such as an acrylic resinadhesive agent, a moisture-curing adhesive agent, and the like.

Note that in FIG. 1, the application points E1 and E2 are illustrated onthe upper surface of the iron core lamina A for convenience of thedescription, but the application points E1 and E2 are actually set onthe lower surface of the iron core lamina A so that the adhesive agentis applied to the lower surface (adhesive agent applying surface) of theiron core lamina A.

As illustrated in FIG. 2, the steps of manufacturing the laminated ironcore include preliminary punching steps 1 to 5, an adhesive agentapplying step 6, an outer shape punching step 7, a rotative stackingstep 8, and a heating step 9 in sequence in accordance with theintermittent conveyance of the strip F in the progressive die machine (amanufacturing apparatus for the laminated iron core).

In the preliminary punching steps, punching 1 of pilot holes P, punching2 of an inner shape rough hole d1 and through holes D, punching 3 ofslots S1, punching 4 of an inner shape d2, and punching 5 of slits S2between teeth and tooth tip groove-shaped sections m are sequentiallyperformed on the strip F by die sets (not shown) each formed by a punchand a die having shapes corresponding to the related punching, whereby abasic shape besides the outer shape punching of the iron core lamina Ais formed.

The adhesive agent applying step 6 is performed following thepreliminary punching steps 1 to 5. The application of the adhesive agentto the strip F is performed on the plurality of application points E1set in positions corresponding to the slots S1 of the yoke section B andthe application points E2 set in two positions on each teeth portion C,in a round dot shape as illustrated in detail in FIG. 1. Here, awell-known anaerobic adhesive agent is used as the adhesive agent. InFIG. 2 also, the application points E1 and E2 are illustrated on theupper surface side of the iron core lamina A for convenience of thedescription, but the application points E1 and E2 are actually set onthe lower surface side of the iron core lamina A.

The outer shape punching step 7 is performed after the adhesive agentapplying step 6 is finished. The outer shape punching step 7 isperformed by a die set (not shown) formed by a punch and a die having ashape corresponding to an outer shape d3 of the iron core lamina A.

The rotative stacking step 8 is performed following the outer shapepunching step 7. The die for the outer shape punching step 7 is arotatable die, and rotates about the central axis line thereof by apredetermined angle, for example, 90 degrees each time the outer shapepunching of one iron core lamina A is performed. As a result, whilechanging the position about the central axis line, the iron core laminaeA punched in the outer shape punching step 7 are sequentially stacked onan iron core lamina group G that has been already punched out andstacked in the rotatable die. By this rotative stacking, the influenceof minute thickness fluctuations that may be present in the iron corelaminae A can be eliminated, and the stack height of the product(laminated iron core) can be managed with high accuracy. Then, the ironcore lamina group G is sequentially pushed into a squeeze ring (notshown) positioned below the rotatable die.

When a newly punched iron core lamina A is stacked on the iron corelamina group G, the lower surface of the newly punched iron core laminaA comes into close contact with the upper surface of the iron corelamina A located in the uppermost layer of the iron core lamina group G.As a result, the adhesive agent applied on the application points E1 andE2 on the lower surface of the newly punched iron core lamina A in around dot shape is mixed with a hardening accelerator applied in advanceon the upper surface of the iron core lamina A located in the uppermostlayer.

The heating step 9 is performed following the rotative stacking step 8is finished. A heating apparatus (not shown) is provided in a lowerportion of the squeeze ring, and the iron core lamina group G is heatedby the heating apparatus while moving downward. Thereby, the adhesiveagent between the iron core laminae A is heated and cured so that thebond strength can be increased. As the heating apparatus for theadhesive agent described above, a heater apparatus that blows hot air tothe iron core lamina group G can be used, for example. After the heatingby the heating apparatus, the iron core lamina group G is separated atpositions of the iron core laminae A for separation, whereby a laminatediron core M formed by a predetermined number of the iron core laminae Ais obtained.

Next, one embodiment of a manufacturing apparatus 10 for the laminatediron core is described with reference to FIG. 4 and FIG. 5. Note that,in the description below, description will be made of simplified ironcore laminae W having an annular shape as illustrated in FIG. 3 tosimplify the description. Each iron core lamina W is formed by punchinga circular inner shape IS and punching a circular outer shape OS, andthe adhesive agent is applied in a dot shape on application points E setin a plurality of positions in a circumferential direction on the lowersurface (adhesive agent applying surface) of an annular portion Robtained by the punching steps.

The manufacturing apparatus 10 employs a progressive die system, andincludes a pilot hole punching station I, an inner shape punchingstation II, an idle station III, an adhesive agent applying station IV,an idle station V, an outer shape punching station VI, and an idlestation VII in sequence in the progressive direction as illustrated inFIG. 4 and FIG. 5. The stations I, II, IV, and VI other than the idlestations III, V, and VII execute the steps in accordance with theintermittent conveyance of the strip F in the progressive direction.Note that sections to be punched in the pilot hole punching station I,the inner shape punching station II, and the outer shape punchingstation VI are indicated by diagonal lines. In the idle stations III, V,and VII, idle feeding of the strip F is performed.

The manufacturing apparatus 10 includes a plate-like upper holder 12fixed to the lower surface of an upper ram (not shown) of a pressmachine, and a plate-like lower holder 14 fixed to the upper surface ofa lower table (not shown) of the same press machine so as to directlyface the upper holder 12.

Punches 20 for pilot hole punching, a punch 22 for inner shape punching,and a punch 24 for outer shape punching are attached on the lower sideof the upper holder 12 at positions corresponding to the stations I, II,and VI by a back plate 16 and a punch plate 18.

A stripper 28 is supported at a place below the upper holder 12 byhanger bolts (not shown) so as to be displaceable in the verticaldirection. The most lowered position of the stripper 28 with respect tothe upper holder 12 is set by hanging support by the hanger bolts (notshown). The stripper 28 is formed as a joined body of a plate-likestripper main body 30 and a stripper plate 32, and a lower surface 33 ofthe stripper plate 32 directly faces an upper surface 47 of a die plate40 and dies 42, 44, and 46 described below. In other words, the stripperplate 32 has the lower surface 33 that directly faces the upper surface47 of the die plate 40 and the dies 42, 44, and 46. Punch insertionholes 34, 36, and 38 through which punches 20, 22, and 24 pass areformed in the stripper plate 32.

The plate-like die plate 40 is attached to the upper surface of thelower holder 14. A die 42 for pilot hole punching, a die 44 for innershape punching, and a die 46 for outer shape punching are attached tothe die plate 40 at positions corresponding to the punching stations I,II, and VI. The punches 20 for pilot hole punching and the respectivedies 42 for pilot hole punching, the punch 22 for inner shape punchingand the die 44 for inner shape punching, and the punch 24 for outershape punching and the die 46 for outer shape punching each correspondto each other, and each form a die set.

Note that the upper surfaces of the die plate 40, the dies 42, the die44, and the die 46 are flush with each other, and hence those uppersurfaces are hereinafter collectively referred to as the upper surface47 of the die plate 40.

An adhesive agent applying apparatus 50 is provided in a part of the dieplate 40 corresponding to the adhesive agent applying station IV. Theadhesive agent applying apparatus 50 is vertically moved by a cammechanism 52 driven by a driving apparatus 54, and when in a raisedposition, applies (transfers) the adhesive agent on the plurality ofsections (application points E) on the lower surface of the strip F in adot shape for each press operation except for when forming an iron corelamina for separation to set the number of the iron core laminae W to bestacked.

In the pilot hole punching station I, the pilot holes P (see FIG. 4) arepunched in the strip F by the punches 20 for pilot hole punching and thedies 42 for pilot hole punching for each press operation, in otherwords, for each intermittent conveyance of the strip F. The pilot holesP are formed near the edge portions on both sides (both of right andleft sides) with respect to the direction (progressive direction) inwhich the strip F is conveyed in an intermittent manner.

In the inner shape punching station II, the inner shape IS (see FIG. 4)is punched in the strip F by the punch 22 for inner shape punching andthe die 44 for inner shape punching for each intermittent conveyance ofthe strip F.

In the adhesive agent applying station IV, the adhesive agent is appliedto the application points E on the lower surface of the strip F in around dot shape by the adhesive agent applying apparatus 50 in theraised position. Note that, when forming an iron core lamina forseparation to set the number of the iron core laminae W to be stacked,which takes place every predetermined number of times of theintermittent conveyance, the adhesive agent applying apparatus 50descends to a lowered position, and hence the application of theadhesive agent to the strip F is suspended.

In the outer shape punching station VI, the outer shape OS (see FIG. 4)is punched in the strip F by the punch 24 for outer shape punching andthe die 46 for outer shape punching. This punching provides a completediron core lamina W. The produced iron core laminae W descend and aresequentially stacked in the die 46 for outer shape punching. Of the ironcore laminae W stacked in the die 46 for outer shape punching,vertically adjoining iron core laminae W are bonded to each other by theadhesive agent applied on the application points E, except for the ironcore laminae W for separation on which the adhesive agent is notapplied.

In the outer shape punching station VI, the stack of the iron corelaminae W is taken out downward from an outlet hole 48 formed in thelower holder 14 and is carried to a post-treatment step for heat-curingthe adhesive agent, as necessary.

Next, the details of the adhesive agent applying apparatus 50 aredescribed with reference to FIG. 6 and FIG. 7.

The adhesive agent applying apparatus 50 is a transfer type, andincludes an application table 60 implemented as a connected body formedby an upper block 58 and a lower block 59. The application table 60 isvertically movably inserted through a holding hole 56 formed in thelower holder 14 and the die plate 40.

The cam mechanism 52 is provided below the application table 60. The cammechanism 52 includes a fixed cam 74 formed by a plate cam fixed to thebottom portion of the lower block 59, and a moving cam 76 formed by aplate cam moveably provided on the bottom portion of the lower block 59.The moving cam 76 is connected to the driving apparatus 54, and isdriven in a reciprocating manner in the right and left directions by thedriving apparatus 54 when seen in FIG. 6. The fixed cam 74 includes asawtooth shape portion having sawtooth protrusions 74A and sawtoothrecesses 74B arranged alternately in the right and left directions onthe lower surface thereof, and the moving cam 76 includes a sawtoothshape portion having sawtooth protrusions 76A and sawtooth recesses 76Barranged alternately on the upper surface thereof.

As illustrated in the drawings, when the moving cam 76 is in a positionin which the sawtooth protrusions 74A of the fixed cam 74 and thesawtooth protrusions 76A of the moving cam 76 are aligned with eachother, the application table 60 is placed in the raised position(transfer position). In the raised position, an upper surface 61 of theupper block 58 is located below the upper surface 47 of the die plate 40by a level difference α.

When the moving cam 76 is driven to the left by the driving apparatus 54when seen in FIG. 6 and the moving cam 76 is placed in a position inwhich the sawtooth recesses 74B of the fixed cam 74 and the sawtoothprotrusions 76A of the moving cam 76 are aligned with each other, theapplication table 60 and the fixed cam 74 descend (retreat downward),and the application table 60 is placed in the lowered position. In thelowered position (non-transfer position), the upper surface 61 of theupper block 58 is placed below the upper surface 47 of the die plate 40by a large level difference that is larger than the level difference α.

The upper block 58 is provided with an adhesive agent accumulationportion 62 formed by an annular groove, and a plurality of dischargeholes 64 each extending from the adhesive agent accumulation portion 62to the horizontal upper surface 61 of the upper block 58 in the up-downdirection (vertical direction) so as to be opened in the upper surface61. The discharge holes 64 are placed in positions corresponding to theapplication points E of the strip F (iron core lamina W) located in theadhesive agent applying station IV.

An inner block 66 is attached in the upper block 58. The inner block 66is formed with adhesive agent supplying passages 68 for supplying theadhesive agent to the adhesive agent accumulation portion 62. A flexibleadhesive agent supplying tube 70 is connected to each adhesive agentsupplying passage 68. The adhesive agent supplying tube 70 is connectedto the adhesive agent supplying apparatus 72. The adhesive agentsupplying apparatus 72 pressurizes the adhesive agent to a predeterminedpressure, measures the pressurized adhesive agent, and supplies thepressurized adhesive agent to the adhesive agent accumulation portion 62with a predetermined flow rate via the adhesive agent supplying tubes 70and the adhesive agent supplying passages 68. Thereby, the adhesiveagent is constantly supplied to the discharge holes 64 from the adhesiveagent accumulation portion 62 with a predetermined pressure.

Note that, in this embodiment, two adhesive agent supplying tubes 70 andtwo adhesive agent supplying passages 68 are provided and the adhesiveagent is supplied to two sections of the adhesive agent accumulationportion 62 that are 180 degrees apart from each other in thecircumferential direction, but this configuration is not essential. Thenumber and the supplying positions only need to be a number andsupplying positions that are necessary in order to ensure the supplyamount of the adhesive agent for maintaining the pressure of theadhesive agent in the entire area of the adhesive agent accumulationportion 62 at an appropriate pressure. The appropriate pressure of theadhesive agent is determined in accordance with the size and the numberof the discharge holes 64, the arrangement of the discharge holes 64,and the like.

The adhesive agent in the adhesive agent accumulation portion 62 isdischarged from the discharge holes 64 to a place above the applicationtable 60. Since the pressure of the adhesive agent in the adhesive agentaccumulation portion 62 is maintained at a predetermined value and theadhesive agent has a predetermined viscosity, the adhesive agentdischarged to the outside from the discharge holes 64 constantly forms abulging portion N that is bulging above the upper surface 61 of theupper block 58 in a substantially hemispherical shape as illustrated inFIG. 7. The height of the bulging portion N is slightly larger than thelevel difference α. Therefore, when the application table 60 is in theraised position (transfer position) and the strip F descends to aposition in which the lower surface of the strip F comes into contactwith the upper surface 47 of the die plate 40, the bulging portion N ofthe adhesive agent of each of the discharge holes 64 comes into contactwith the lower surface of the strip F, and the adhesive agent istransferred to the application points E in a round dot shape.

If the adhesive agent applying apparatus 50 intermittently forms thebulging portions N, the timing is set so that the bulging portions N areformed when the strip F is placed in a position where the lower surfaceof the strip F is in contact with the upper surface 47 of the die plate40. As a result, the adhesive agent is transferred to the applicationpoints E in a round dot shape in a state in which the lower surface ofthe strip F is in contact with the upper surface 47 of the die plate 40.

The transfer amount of the adhesive agent on the application points Ecan be controlled in accordance with the level difference α and the size(volume) of the bulging portion N. The size of the bulging portion N isquantitatively determined in accordance with the pressure of theadhesive agent in the adhesive agent accumulation portion 62, theviscosity of the adhesive agent, the inner diameter of the dischargeholes 64, and the like, and hence the transfer amount of the adhesiveagent on the application points E can be set to an optimal value byoptimally setting those factors.

In the transfer-type application of the adhesive agent using thedischarge holes 64 as above, the minimum pitch between the applicationpoints E can be set to a size that is slightly larger than the innerdiameter of the discharge holes 64 by reducing the pitch between theadjacent discharge holes 64. As a result, even when the teeth portion Cis small, the application points E can be set in a plurality of sectionsin the teeth portion C. This contributes to the enhancement of the bondstrength of the teeth portion C in the lamination bonding of theplurality of iron core laminae W.

When the application table 60 is in the lowered position (non-transferposition), the upper surface 61 of the upper block 58 is placed belowthe upper surface 47 of the die plate 40 by a large level differencethat is larger than the level difference α. As a result, the bulgingportion N of the adhesive agent having a defined size does not come intocontact with the lower surface of the strip F, and the adhesive agent isnot transferred to the lower surface of the strip F. Therefore, theapplication table 60 only needs to be moved to the lowered position whenforming an iron core lamina for separation to set the number of the ironcore laminae W to be stacked.

As illustrated in FIG. 8A and FIG. 8B, knock-outs 26 are attached to theupper holder 12. Note that FIG. 8A illustrates the inner shape punchingstation II as a representative example of the punching stations, andFIG. 8B illustrates the adhesive agent applying station IV.

Each knock-out 26 includes a lower end 26A in abutment with the upperportion of the stripper main body 30, a shaft portion 26C fitted in athrough hole 13 formed in the upper holder 12 in a vertically movablemanner, and an upper end flange 26B located in a spring chamber 15formed in the upper holder 12. The upper portion of the spring chamber15 is closed by a plug 17 fixed to the upper holder 12. A stripperspring 29 (a knock-out spring) consisting of a compression coil springis provided between the plug 17 and the upper end flange 26B. Thestripper spring 29 biases the knock-out 26 downward.

As illustrated in FIG. 12A and FIG. 12B, the most lowered position(bottom dead center position) of the upper holder 12 is determined byabutment of the lower surface of the upper holder 12 against the uppersurface of stoppers 82 provided on both of right and left sides of thelower holder 14 at the bottom dead center of the upper ram (not shown)of the press machine. When the upper holder 12 is placed in the mostlowered position, the stripper plate 32 comes into abutment with thestrip F and presses the strip F against the upper surface 47 of the dieplate 40 while being displaced with respect to the upper holder 12 tocause the compressive deformation of the stripper springs 29.

A relative displacement stroke of the stripper 28 with respect to theupper holder 12 in the vertical direction is larger than the enteringstroke of the punches 20, 22, and 24 with respect to the dies 42, 44,and 46. As illustrated in FIG. 12A, the entering stroke is a strokecorresponding to the entering amount by which the punches 20, 22, and 24enter the dies 42, 44, and 46 in a state in which the upper holder 12 isin the most lowered position.

That is, the stripper 28 including the stripper plate 32 is formed sothat the stroke between the most lowered position of the stripper 23with respect to the upper holder 12 and the position in which thestripper 28 presses the strip F against the upper surface 47 of the dieplate 40 of the lower holder 14 after moving relative to the upperholder 12 to cause the elastic deformation of the stripper spring 29 islarger than the maximum entering stroke by which the punches 20, 22, and24 enter the dies 42, 44, and 46.

Owing to this stroke setting, in the ascending process of the upperholder 12 after the punching, the punches 20, 22, and 24 are pulled outfrom the dies 42, 44, and 46 and the strip F, and thereafter, thestripper 28 ascends together with the upper holder 12 and the pressingof the strip F by the stripper 28 is released. As a result, the state inwhich the strip F is pressed against the upper surface 47 of the dieplate 40 by the stripper 28 is maintained until the punches 20, 22, and24 come out of the dies 42, 44, and 46.

As illustrated in FIG. 8A, in the stations II to VII other than thepilot hole punching station I, a pilot pin 84 capable of entering apilot hole P in the strip F is provided in each of the stations II toVII. Note that the illustration of the pilot pin 84 provided in theadhesive agent applying station IV is omitted in FIG. 8B.

Each of the pilot pins 84 includes an upper end flange 84A, a straightshaft portion 84B, and a lower end tapered shaft portion 84C in sequencein the axial direction. Each of the pilot pins 84 is inserted in amounting hole 86 formed in the upper holder 12, and vertically passesthrough a through hole 88 formed in the back plate 16 and the punchplate 18 and a through hole 90 formed in the stripper 28 in a slidablemanner. The lower end tapered shaft portion 84C as well as a lower partof the straight shaft portion 84B protrude downward from the lowersurface 33 of the stripper plate 32 in the most lowered position withrespect to the upper holder.

Owing to the above setting, in the descending process of the upperholder 12, the straight shaft portions 84B of the pilot pins 84 enterthe corresponding pilot holes P before the lower surface 33 of thestripper plate 32 comes into abutment with the strip F, wherebypositioning of the strip F is performed in the progressive direction aswell as in a direction orthogonal to the progressive direction on theupper surface 47 of the die plate 40, that is, in the right and leftdirections.

The most lowered position (lower limit position) of each of the pilotpins 84 is set by abutment of the lower surface of the upper end flange84A against the upper surface of the back plate 16 forming a bottomsurface of the mounting hole 86. Each of the pilot pins 84 is biaseddownward by the spring force of the compression coil spring 94 providedbetween a plug 92, which is fixed to the upper holder 12 to close theupper portion of the mounting hole 86, and the upper end flange 84A. Thespring-biased structure is a relief structure for avoiding damage to thepilot pin 84 when the pilot pin 84 does not correctly enter the pilothole P. Note that the die plate 40 is provided with pin relief holes 41in which the pilot pins 84 enter.

Next, a feed guide structure and a lift up structure of the strip F aredescribed with reference to FIG. 4, FIG. 8A, and FIG. 8B. On the lowerholder 14, that is, on the die plate 40 fixed to the lower holder 14 inthe illustrated embodiment, right and left guiding members 100 thatguide the conveyance of the strip F, which is a thin steel sheet, in adirection along the direction in which the strip F is conveyed in anintermittent manner (progressive direction) are symmetrically attached.The right and left guiding members 100 each have a strip-like shape thatis long in the progressive direction of the strip F, and, as illustratedin FIG. 4, are provided at intervals in the progressive direction of thestrip F except for regions corresponding to the stations II, IV, and VI.

As illustrated in FIG. 16, the right and left guiding members 100 eachhave a lower surface 102 formed by a horizontal wall opposing the uppersurface 47 of the die plate 40 from above with a predetermined distanceT therebetween, and a side surface 103 formed by a vertical wallopposing the right or left end surface of the strip F with apredetermined gap therebetween, such that the side portions of the rightand left guiding members 100 opposed to each other have a hook-likecross-sectional shape. The lower surfaces 102 and the side surfaces 103of the guiding members 100, and the upper surface 47 of the die plate 40cooperate with each other to define right and left guide grooves 104extending in the progressive direction of the strip F and having arectangular cross-sectional shape with an inward facing opening.

The right and left side edge portions of the strip F enter the right andleft guide grooves 104, respectively. As a result, the guiding members100 guide the intermittent conveyance of the strip F by limiting themovement of the strip F in the right and left directions with the sidesurfaces 103 and limiting the upward movement of the strip F with thelower surfaces 102.

Consequently, the shifting of the strip F in the right and leftdirections and the vertical direction is suppressed when the strip F isconveyed in an intermittent manner, and the movement of the strip F inthe right and left directions and in the upward direction with respectto the upper surface 47 of the die plate 40 is limited when the adhesiveagent is applied to the adhesive agent applying surface (lower surface)of the strip F. As a result, the adhesive agent is accurately applied onthe adhesive agent applying surface. Note that, by being placed on theupper surface 47 of the die plate 40 or by being lifted up by lifterpins 110 described below, the downward movement of the strip F islimited (prevented).

The abovementioned predetermined distance T is larger than the total ofa lift up amount L of the strip F by the lifter pins 110 described belowand the thickness of the strip F. With this setting, even when the stripF is lifted up by the lifter pins 110, the strip F does not come intoabutment with the lower surfaces 102 of the guiding members 100. As aresult, the upper surface of the strip F does not come into slidingcontact with the lower surfaces 102 of the guiding members 100 when thestrip F is conveyed in an intermittent manner, and the guiding members100 do not increase the frictional resistance when the strip F isconveyed in an intermittent manner.

As illustrated in FIG. 4, the lifter pins 110 are provided on both ofright and left sides of the die plate 40 with a predetermined intervalin the progressive direction of the strip F. The arrangement positionsof the lifter pins 110 overlap with the arrangement positions of theguiding members 100 in plan view.

As illustrated in FIG. 8A and FIG. 8B, the lifter pins 110 are providedin lifter pin holes 112 so as to be displaceable in the verticaldirection. The lifter pin holes 112 are formed in the die plate 40 andthe lower holder 14 so as to open in the upper surface 47 of the dieplate 40. The upper end side of each lifter pin 110 is exposed on theupper surface 47 of the die plate 40. Lifter springs 114 each consistingof a compression coil spring are provided between the lifter pins 110and the bottom portions of the lifter pin holes 112. The lifter springs114 bias the corresponding lifter pins 110 upward.

About half of the upper end surface of each of the lifter pins 110 cancome into abutment with the lower surface of the strip F, and theremaining half can come into abutment with a stopper surface 106 formedon each of the guiding members 100. As a result, as illustrated in FIG.8A, FIG. 8B, and FIG. 16, when the strip F is not pressed down by thestripper 28, the lifter pins 110 are placed in the raised position inwhich the upper end surfaces are in abutment with the stopper surface106 by the spring bias of the lifter springs 114, and raise (lift up)the strip F from the upper surface 47 of the die plate 40. When thestrip F is pressed down by the stripper 28, as illustrated in FIG. 11A,FIG. 11B, and FIG. 18, the lifter pins 110 are lowered by the strip Fagainst the spring force of the lifter springs 114, and entirely sinkinto the lifter pin holes 112.

As illustrated in FIG. 16, the lift up amount L of the strip F by thelifter pins 110 is determined by abutment of the upper surfaces of thelifter pins 110 against the stopper surfaces 106 of the guiding members100 facing downward, and the lift up amount L is set to a value that islarger than the applying thickness (maximum thickness) of the adhesiveagent transferred to the lower surface of the strip F.

Next, with reference to FIG. 8A, FIG. 8B to FIG. 15A, FIG. 15B, and FIG.16 to FIG. 19, the operation of the manufacturing apparatus 10 by theabovementioned configuration is described. Note that FIG. 8A to FIG. 15Aillustrate the operation of the inner shape punching station II as arepresentative example of the punching stations, and FIG. 8B to FIG. 15Billustrate the operation of the adhesive agent applying station IV. Theoperation of the pilot hole punching station I and the outer shapepunching station VI is substantially the same as the operation of theinner shape punching station II, and hence the description of theoperation is omitted.

FIG. 8A and FIG. 8B illustrate, as a press starting state, a state inwhich the upper ram (not shown) of the press machine is at the top deadcenter and the upper holder 12 is at the most raised position (top deadcenter position). In this press starting state, the punch 22 for innershape punching, the stripper 28, and the pilot pin 84 are in a positionseparated from the die plate 40 in the upward direction. The strip F isin a raised position (lift up state) where the strip F is separated fromthe upper surface 47 of the die plate 40 by the lifter pins 110 (seeFIG. 16). In the lift up state, the strip F is conveyed by anintermittent feed apparatus (not shown) in an intermittent manner (by apredetermined amount for each intermittent conveyance) in theprogressive direction without the lower surface of the strip F cominginto sliding contact with the upper surface 47 of the die plate 40.

Upon completion of one intermittent conveyance or during an intermittentconveyance process, the upper holder 12 starts to descend from the topdead center position, as illustrated in FIG. 9A and FIG. 9B. As thedescent of the upper holder 12 proceeds, the straight shaft portion 84Benters the pilot hole P in the strip F following the lower end taperedshaft portion 84C of the pilot pin 84 before the stripper 28 presses thestrip F against the upper surface 47 of the die plate 40, as illustratedin FIG. 10A and FIG. 10B. As a result, the positioning of the strip Fwith respect to the manufacturing apparatus 10 in the conveyancedirection (progressive direction) and in the right and left directionsis performed.

The positioning is performed in a state in which the strip F is liftedup from the upper surface 47 of the die plate 40, and hence the movementof the strip F in the conveyance direction and the right and leftdirections for positioning with respect to the manufacturing apparatus10 is performed with low frictional resistance.

As illustrated in FIG. 11A and FIG. 11B, as the descent of the upperholder 12 further proceeds, the lower surface 33 of the stripper plate32 comes into abutment with the upper surface of the strip F (see FIG.17), and the stripper 28 pushes the strip F together with the lifterpins 110 down to a position in which the strip F is in abutment with theupper surface 47 of the die plate 40 against the spring force of thelifter springs 114 (see FIG. 18). Note that, at this time, owing to theoverall setting of the spring force of the stripper springs 29 and thelifter springs 114, the stripper springs 29 do not compressively deform,and the stripper 28 is maintained to be in the most lowered positionwith respect to the upper holder 12.

As illustrated in FIG. 12A and FIG. 12B, as the descent of the upperholder 12 further proceeds, the stripper springs 29 compressivelydeform, the upper holder 12 descend with respect to the stripper 28, andthe lower surface of the upper holder 12 is placed at the bottom deadcenter to be in abutment with the upper surface of the stopper 82. As aresult, as illustrated in FIG. 12A, in the inner shape punching stationII, the punch 22 for inner shape punching enters the die 44 for innershape punching while the strip F is in a clamped state in which thestrip F is pressed against the upper surface 47 of the die plate 40 bythe stripper 28 biased by the springs, and the punching of the innershape IS is performed. In addition, in the adhesive agent applyingstation IV, when the strip F is pressed against the upper surface 47 ofthe die plate 40 by the stripper 28 biased by the springs, the bulgingportions N of the adhesive agent discharged from the discharge holes 64are transferred to the corresponding application points E on the lowersurface of the strip F (see FIG. 7).

The transfer of the adhesive agent is performed in a state in which themovement of the strip F in the right and left directions is limited andthe upward movement of the strip F is limited by the guiding members100, and the positioning of the strip F is performed by the pilot pin84. Therefore, even in a case where the application points E are small,the adhesive agent is accurately transferred to the application points Ewith high position accuracy.

In addition, the transfer of the adhesive agent is performed in a statein which the lower surface of the strip F is pressed against the uppersurface 47 of the die plate 40 and thus the strip F cannot vibrate.Therefore, even when the punching of the inner shape IS and the transferof the adhesive agent are simultaneously performed, the transfer of theadhesive agent can be performed without the vibrations of the hoopmaterial F caused by the punching shock in the inner shape punchingstation II, and the adhesive agent is accurately transferred to theapplication points E. This also contributes to allowing the adhesiveagent to be accurately transferred to the application points E with highposition accuracy even when the application points E are small.

As illustrated in FIG. 13A and FIG. 13B, when the punching of the innershape IS and the transfer of the adhesive agent are finished, the upperholder 12 starts ascending from the bottom dead center. When the upperholder 12 ascends from the bottom dead center, the punch 22 for innershape punching first comes out of the die 44 for inner shape punching inthe upward direction. As described above, the stroke in which thestripper 28 moves relative to the upper holder 12 is larger than themaximum entering stroke in which the punch 22 for inner shape punchingenters the die 44 for inner shape punching. Therefore, a state in whichthe strip F is pressed against the upper surface 47 of the die plate 40by the stripper 28 is maintained until the punch 22 for inner shapepunching comes out of the die 44 for inner shape punching.

As a result, even when vibration occurs by the friction when the punch22 for inner shape punching comes out of the die 44 for inner shapepunching and the punching opening in the strip F, the vibration is nottransmitted to the part of the strip F in the adhesive agent applyingstation IV, whereby the transfer shape of the adhesive agent transferredto the application points E on the hoop material F does not lose shapeor the adhesive agent is not scattered.

As illustrated in FIG. 14A and FIG. 14B, as the ascent of the upperholder 12 proceeds, the stripper 28 ascends together with the upperholder 12, the lifter pins 110 ascend by the spring force of the liftersprings 114, and the strip F is lifted up. The lifter pins 110 come intoabutment with the stopper surfaces 106, and hence the strip F returns toa raised position (lift up state) separated from the upper surface 47 ofthe die plate 40.

As illustrated in FIG. 19, the ascent of the strip F is performed in astate in which the strip F is prevented from shifting to the right andleft directions by the guiding members 100, the stripper 28 is inabutment with the upper surface of the strip F, the lifter pins 110 arein abutment with the lower surface of the strip F, and the strip F isvertically supported by the stripper 28 and the lifter pins 110.Therefore, the swinging of the strip F in the ascending process issuppressed. As a result, in the ascending process (lift up process) ofthe strip F, the transfer shape of the adhesive agent transferred to theapplication points E on the strip F is prevented from losing shape orthe adhesive agent is prevented from being scattered.

As illustrated in FIG. 15A and FIG. 15B, as the ascent of the upperholder 12 further proceeds, the pilot pin 84 comes out of the pilot holeP in the upward direction. Then, the upper holder 12 returns to the topdead center position illustrated in FIG. 8A and FIG. 8B. Theintermittent conveyance of the strip F starts at the time point at whichthe pilot pin 84 comes out of the pilot hole P. The intermittentconveyance is performed in a state in which the strip F is lifted up bythe lifter pins 110 and the lower surface is separated from the uppersurface 47 of the die plate 40 by the lift up amount L (see FIG. 16).Therefore, the adhesive agent transferred to the application points E onthe lower surface of the strip F is not rubbed by the upper surface 47of the die plate 40.

The intermittent conveyance is performed in a state in which the upwardmovement of the strip F is limited and the shifting of the strip F inthe right and left directions is limited by the guiding members 100.Therefore, in the conveyance process of the strip F, the transfer shapeof the adhesive agent transferred to the application points E on thestrip F does not lose shape or the adhesive agent is not scattered. Theintermittent conveyance finishes before the next punching step starts.

By the above, the adhesive agent is accurately applied on the adhesiveagent applying surface of each iron core lamina W. In addition, theadhesive agent applied on the adhesive agent applying surface of eachiron core lamina W does not spread to the surroundings and the transfershape does not lose shape or the adhesive agent is not scattered. Thus,high-quality laminated iron cores can be stably produced even when theyare small in size.

As another embodiment, as illustrated in FIG. 20, the pilot holes P maybe formed in positions corresponding to places directly below pilot pinguide holes 108 formed in the guiding members 100 so as to passtherethrough. In that case, the pilot pins 84 are inserted into thepilot holes P with high accuracy in a state in which the flapping of thestrip F is suppressed. In addition, each pilot pin 84 (see FIG. 8A)passes through the pilot pin guide hole 108 and enters the pilot hole P,and hence the positioning accuracy of the strip F by the pilot pins 84is enhanced.

Next, another embodiment of the manufacturing apparatus 10 for thelaminated iron core is described with reference to FIG. 21, FIG. 22A,and FIG. 22B. Note that, in FIG. 21, FIG. 21A, and FIG. 21B, the partscorresponding to those shown in FIG. 4, FIG. 8A and FIG. 8B are denotedby the same reference characters as the reference characters in FIG. 4,FIG. 8A and FIG. 8B, and description thereof is omitted.

In this embodiment, as illustrated in FIG. 21, the guiding members 100are omitted, and lifter pins 120 also serve as the guiding members ofthe strip F. The lifter pins 120 are provided on both of right and leftsides of the die plate 40, and the lifter pins 120 are provided with apredetermined interval therebetween in the progressive direction of thestrip F.

As illustrated in FIG. 22A and FIG. 22B, the lifter pins 120 areprovided in lifter pin holes 122 so as to be displaceable in thevertical direction, and the upper end portions thereof protrude from theupper surface 47 of the die plate 40. The lifter pin holes 122 areformed in the die plate 40 and the lower holder 14 so as to open in theupper surface 47 of the die plate 40. Lifter springs 124 each consistingor a compression coil spring are provided between the lifter pins 120and the bottom portions of the lifter pin holes 122. The lifter springs124 bias the corresponding lifter pins 120 upward. When the strip F isnot pressed down by the stripper 28, each lifter pin 120 is placed in araised position in which a step portion 120A is in abutment with ashoulder portion 116 provided at a junction between the die plate 40 andthe lower holder 14 by the spring bias of the lifter spring 124, andwhen the strip F is pressed down by the stripper 28, each lifter pin 120is placed in a lowered position in which the lifter pin 120 is loweredby the strip F against the spring force of the lifter spring 124.

The lifter pins 120 each have a circumferential groove 126 in the outercircumference of a part protruding from the upper surface 47 of the dieplate 40. The circumferential grooves 126 each have a rectangularcross-sectional shape as with the guide grooves 104 in theabovementioned embodiment. The right and left side edge portions of thestrip F enter the circumferential grooves 126, and hence the strip F israised (lifted up) from the upper surface 47 of the die plate 40 in theraised position, and the strip F is placed on the upper surface 47 ofthe die plate 40 in the lowered position. In addition, with the rightand left side edge portions of the strip F entering the circumferentialgrooves 126 in the right and left lifter pins 120, the lifter pins 120limit the movement of the strip F in the right and left directions andguide the intermittent conveyance of the strip F, and also limit thedownward movement of the strip F in addition to the upward movement ofthe strip F when lift up is performed.

As a result, when the strip F is conveyed in an intermittent manner orwhen the adhesive agent is applied to the adhesive agent applyingsurface, the shifting of the strip F in the right and left directionsand the upward and downward movement of the strip F are limited. By thislimitation, the flapping of the strip F is suppressed, and the adhesiveagent is accurately applied on the adhesive agent applying surface.

This embodiment is substantially the same as the abovementionedembodiment other than the abovementioned lift up structure of the stripF by the lifter pins 120, and hence the effect of the abovementionedembodiment is obtained also in this embodiment.

In this embodiment, the lifter pins 120 also serve as the guidingmembers of the strip F, and hence the number of parts is reduced.

Other embodiments of the manufacturing apparatus for the laminated ironcore according to the present invention are as follows.

(1) A manufacturing apparatus for a laminated iron core formed bystacking and bonding iron core laminae each formed by punching a sheetsteel strip into a predetermined shape, the manufacturing apparatusincluding: an upper holder and a lower holder; a plurality of punchesand dies provided on the upper holder and the lower holder,respectively, the plurality of punches and dies sequentially punchingthe iron core laminae from the sheet steel strip conveyed in anintermittent manner; a pilot pin provided on the upper holder, the pilotpin being configured to be inserted through a pilot hole formed in thesheet steel strip so as to perform positioning of the sheet steel stripin each conveyance position; and an adhesive agent applying apparatusprovided on at least one of the upper holder and the lower holder, theadhesive agent applying apparatus applying an adhesive agent to anadhesive agent applying surface at a section of the sheet steel stripcorresponding to each iron core lamina.

(2) A manufacturing apparatus for a laminated iron core formed bystacking and bonding iron core laminae each formed by punching a sheetsteel strip into a predetermined shape, the manufacturing apparatusincluding: an upper holder and a lower holder; a plurality of punchesand dies provided on the upper holder and the lower holder,respectively, the plurality of punches and dies sequentially punchingthe iron core laminae from the sheet steel strip conveyed in anintermittent manner; a stripper plate provided on the upper holder so asto be displaceable in a vertical direction, the stripper plate having alower surface opposed to upper surfaces of the dies; and an adhesiveagent applying apparatus provided on at least one of the upper holderand the lower holder, the adhesive agent applying apparatus applying anadhesive agent to an adhesive agent applying surface at a section of thesheet steel strip corresponding to each iron core lamina. In that case,the manufacturing apparatus for the laminated iron core may furtherinclude a stripper spring that biases the stripper plate toward thelower holder, and the lower surface of the stripper plate may beconfigured to press the sheet steel strip against the upper surfaces ofthe dies by a spring force of the stripper spring. Further, the stripperplate may be configured to press the sheet steel strip against the uppersurfaces of the dies by the lower surface until the punches comes out ofthe dies.

(3) A manufacturing apparatus for a laminated iron core formed bystacking and bonding iron core laminae each formed by punching a sheetsteel strip into a predetermined shape, the manufacturing apparatusincluding: an upper holder and a lower holder; a plurality of punchesand dies provided on the upper holder and the lower holder,respectively, the plurality of punches and dies sequentially punchingthe iron core laminae from the sheet steel strip conveyed in anintermittent manner; a plurality of lifters provided on the lower holderso as to be displaceable in a vertical direction, the plurality oflifters separating the sheet steel strip from upper surfaces of the diesby coming into abutment with a lower surface of the sheet steel strip;and an adhesive agent applying apparatus provided on at least one of theupper holder and the lower holder, the adhesive agent applying apparatusapplying an adhesive agent to an adhesive agent applying surface at asection of the sheet steel strip corresponding to each iron core lamina.In that case, a plurality of lifter springs that bias the lifters upwardso as to separate the sheet steel strip from the upper surfaces of thedies with the sheet steel strip being vertically supported by thestripper plate and the lifters when the stripper plate ascends may befurther included.

Preferred embodiments of the present invention have been describedabove, but the present invention is not limited to the embodiments asabove and can be modified, as appropriate, without departing from thespirit of the present invention as a person skilled in the art wouldeasily understand.

For example, the application table 60 of the adhesive agent (firstadhesive agent liquid) may repeatedly descend and ascend insynchronization with the press operation instead of descending only wheniron core laminae for separation are formed. The hardening acceleratoror the initiator (second adhesive agent liquid) may be continuouslyapplied or may be applied only when the strip F stops. In addition, thehardening accelerator or initiator (second adhesive agent liquid) may beapplied to the entire strip F or a part of the strip F. In addition, aplurality of the adhesive agent accumulation portions 62 may beprovided, such that the adhesive agent may be supplied to the dischargeholes 64 in respective areas from the adhesive agent accumulationportions 62. The adhesive agent may be continuously supplied to theadhesive agent accumulation portion 62 or may be intermittently suppliedto the adhesive agent accumulation portion 62 in synchronization withthe press operation. The application of the adhesive agent is notlimited to transferring, and a jet-type emission application may beused. The application of the adhesive agent to the strip F may beperformed on the upper surface of the strip F or both surfaces, that is,the lower surface and the upper surface. The application shape of theadhesive agent is not limited to a round dot shape, and may be anannular shape, a triangle, a square, a deformed shape, and the like.

In some types of laminated iron cores, the inner shape punching isunnecessary. In that case, the inner shape punching only needs to beomitted. In addition, the pilot pin 84 is not essential. As the shape ofthe laminated iron core in plan view, a square, a T-shape, a U-shape,and the like may be used besides an annular shape and a circular shape.

The strip F does not necessarily need to be pressed against the uppersurfaces of the die plate 40, the dies 44, 42, and 46, and theapplication table 60 by the stripper plate 32, and the stripper plate 32may be configured to limit the displacement of the strip F in thevertical direction between the stripper plate 32 and the upper surfacesof the die plate 40, the dies 44 and 46, and the application table 60until the punches 22 and 24 come out from the dies 44 and 46.

The arrangement of the stripper plate 32 and the lifter pins 110 may besuch an arrangement in that the stripper plate 32 and the lifter pins110 overlap each other in plan view so as to vertically sandwich thestrip F therebetween other than the arrangement in which the stripperplate 32 and the lifter pins 110 are offset in the right and leftdirections so as not to overlap each other in plan view. The lifter pins110 may be arranged in an intermediate portion in the strip F in theright and left directions.

The application of the adhesive agent by the adhesive agent applyingapparatus 50 is preferred to be performed directly before the outerdiameter punching step in view of the carrying distance of the strip Fafter applying the adhesive agent becoming short, but does notnecessarily need to be directly before the outer diameter punching step.The heating step and the rotative stacking step are not essential.

In addition, not every component described in the abovementionedembodiments is essential, and the components to be employed can beselected, as appropriate, without departing from the gist of the presentinvention. For example, the pilot pins, the guiding members, and thestripper structure are not essential, and may be omitted.

REFERENCE SIGNS LIST

-   10 manufacturing apparatus-   12 upper holder-   13 through hole-   14 lower holder-   15 spring chamber-   16 back plate-   17 plug-   18 punch plate-   20 punch for pilot hole punching-   22 punch for inner shape punching-   24 punch for outer shape punching-   26 knock-out-   26A lower end-   26B upper end flange-   26C shaft portion-   28 stripper-   29 stripper spring-   30 stripper main body-   32 stripper plate-   33 lower surface-   34 punch insertion hole-   36 punch insertion hole-   38 punch insertion hole-   40 die plate-   41 pin relief hole-   42 die for pilot hole punching-   44 die for inner shape punching-   46 die for outer shape punching-   47 upper surface-   48 outlet hole-   50 adhesive agent applying apparatus-   52 cam mechanism-   54 driving apparatus-   56 holding hole-   58 upper block-   59 lower block-   60 application table-   61 upper surface-   62 adhesive agent accumulation portion-   64 discharge hole-   66 inner block-   68 adhesive agent supplying passage-   70 adhesive agent supplying tube-   72 adhesive agent supplying apparatus-   74 fixed cam-   74A sawtooth protruding portion-   74B sawtooth recessed portion-   76 moving cam-   76A sawtooth protruding portion-   76B sawtooth recessed portion-   82 stopper-   84 pilot pin-   84A upper end flange-   84B straight shaft portion-   84C lower end tapered shaft portion-   86 mounting hole-   88 through hole-   90 through hole-   92 plug-   94 compression coil spring-   100 guiding member-   102 lower surface-   103 side surface-   104 guide groove-   106 stopper surface-   108 pilot pin guide hole-   110 lifter pin-   112 lifter pin hole-   114 lifter spring-   116 shoulder portion-   120 lifter pin-   120A step portion-   122 lifter pin hole-   124 lifter spring-   126 circumferential groove-   I pilot hole punching station-   II inner shape punching station-   III idle station-   IV adhesive agent applying station-   V idle station-   VI outer shape punching station-   VII idle station-   T predetermined interval-   L lift up amount-   A iron core lamina-   W iron core lamina-   M laminated iron core-   F strip (sheet steel strip)-   E application point-   E1 application point-   E2 application point-   G iron core lamina group

The invention claimed is:
 1. A manufacturing method for a laminated ironcore formed by laminating and bonding iron core laminae each formed bypunching a sheet steel strip into a predetermined shape with use of apress apparatus comprising an upper holder and a lower holder, themanufacturing method comprising: conveying the sheet steel strip in anintermittent manner in a lift up state in which the sheet steel strip isseparated from an upper surface of a die plate provided on the lowerholder by a lifter provided on the lower holder so as to be verticallymovable and biased upward by a lifter spring in a raised state of theupper holder, with an upward movement of the sheet steel strip beinglimited and conveyance of the sheet steel strip along an intermittentconveyance direction being guided by a guiding member provided on thelower holder; punching an outer shape of each of the iron core laminaewith a punch and a die for outer shape punching included in a pluralityof punches and dies provided on the upper holder and the lower holder,respectively, by lowering the upper holder; applying an adhesive agentto an adhesive agent applying surface of the sheet steel strip with anadhesive agent applying apparatus provided on at least one of the upperholder and the lower holder before the punching of the outer shape ofeach of the iron core laminae; inserting a pilot pin provided on theupper holder into a pilot hole formed in the sheet steel strip in middleof descent of the upper holder after the conveying of the sheet steelstrip finishes; and pressing, in middle of descent of the upper holderafter the inserting of the pilot pin finishes, the sheet steel stripagainst the upper surface of the die plate provided on the lower holderwith a stripper plate provided on the upper holder so as to bedisplaceable in a vertical direction and having a lower surface opposedto the upper surface of the die plate, along with a descending movementof the lifter, the stripper plate being biased toward the lower holderby a stripper spring, wherein the applying of the adhesive agentcomprises applying the adhesive agent in a state in which the pilot pinis inserted in the pilot hole and when the sheet steel strip is about tobe pressed against or is being pressed against the upper surface of thedie plate by the stripper plate along with the descending movement ofthe lifter, and returning the sheet steel strip to the lift up state byraising the upper holder after application of the adhesive agentfinishes, with the lifter being in abutment with a lower surface of thesheet steel strip along with an ascending movement of the lifter andwith the stripper plate being in abutment with the upper surface of thesheet steel strip.
 2. The manufacturing method for a laminated iron coreaccording to claim 1, wherein the applying of the adhesive agentcomprises transferring the adhesive agent to each of application pointsset on a plurality of predetermined positions on the adhesive agentapplying surface by discharging the adhesive agent toward the adhesiveagent applying surface from each of a plurality of discharge holes. 3.The manufacturing method for a laminated iron core according to claim 2,wherein each iron core lamina comprises a plurality of teeth portions,and has at least one of the application points placed on the teethportion.